Libxml2 is the XML C library developed for the
Gnome project. The library code is portable (to
Linux, Unix, Windows, embedded systems, etc.) and
modular; most of the extensions can be compiled
out. Libxml2 implements a number of existing
standards related to markup languages, including
the XML standard, Namespaces in XML, XML Base,
Relax NG, RFC 2396, XPath, XPointer, HTML4,
XInclude, SGML Catalogs, and XML Catalogs. In most
cases, libxml tries to implement the
specifications in a relatively strict way. To some
extent, it provides support for the following
specifications, but doesn't claim to implement
them: DOM, FTP client, HTTP client, and SAX2.
Support for W3C XML Schemas is in progress. It
includes xmllint, a command line XML validator.

getmail is intended as a simple, secure, and
reliable replacement for fetchmail. It retrieves
email (either all messages, or only unread
messages) from one or more POP3, SPDS, or IMAP4
servers (with or without SSL) for one or more
email accounts, and reliably delivers into
qmail-style Maildirs, mboxrd files, or through
external MDAs (command deliveries) specified on a
per-account basis. getmail also has excellent
support for domain (multidrop) mailboxes,
including delivering messages to different users
or destinations based on the envelope recipient
address.

IMDbPY is a Python package useful to retrieve and manage the data of the IMDb movie database about movies, people, characters, and companies. It can retrieve data from both the IMDb's Web server and a local copy of the whole database. The IMDbPY package can be very easily used by programmers and developers to provide access to the IMDb's data to their programs. Some simple example scripts are included in the package.

Xapian is a search engine library, scalable to collections containing hundreds of millions of documents. It's written in C++ with bindings for Perl, Python, PHP, Java, Tcl, C#, Ruby, and Lua. It is a highly adaptable toolkit that allows developers to easily add advanced indexing and search facilities to their own applications. It supports the Probabilistic Information Retrieval model and also a rich set of boolean query operators. Omega is a Web search application built upon the Xapian library. It can index a Web server's document tree (including HTML, PDF, OpenOffice, MS Word/Excel/Powerpoint/Works, WordPerfect, RTF, PS, etc.), or data exported from arbitrary sources (e.g. SQL databases).

Libxslt is a C library for GNOME which allows developers to work with XSLT. It is based on libxml for XML parsing, tree manipulation, and XPath support. Also included is 'xsltproc', a command line XSLT processor. The library is written in plain C, making as few assumptions as possible, and sticking closely to ANSI C/POSIX for easy embedding. It should work on Linux, Unix, and Windows. Though not designed primarily with performances in mind, libxslt seems to be a relatively fast processor. It also include full support for the EXSLT set of extension functions as well as some common extensions present in other XSLT engines.

SQLObject is an object-relational mapper, i.e., a library that will wrap your database tables in Python classes and your rows in Python instances. It currently supports MySQL through the 'MySQLdb' package, PostgreSQL through the 'psycopg' package, SQLite, Firebird, MaxDB (SAP DB), MS SQL, and Sybase. It should support Python versions back to 2.4.

bitstring is a Python module that helps to make the creation and analysis of binary data as simple and natural as possible. Objects can be constructed from integers (big and little endian), floats, hex, octal, binary, byte data, iterables, or files. They can be sliced, joined, reversed, packed, unpacked, inserted into, overwritten, and otherwise operated upon with simple functions or slice notation. They can also be parsed, searched, and navigated in, similar to a file or stream. Internally the data is efficiently stored as byte arrays. It is available for Python 2.6 and later (including Python 3).

Scapy is a powerful interactive packet
manipulation tool, packet generator, network
scanner, network discovery tool, and packet
sniffer. It provides classes to interactively
create packets or sets of packets, manipulate
them, send them over the wire, sniff other packets
from the wire, match answers and replies, and
more. Interaction is provided by the Python
interpreter, so Python programming structures can be used (such as variables, loops, and functions). Report modules are possible and easy to make. It is intended to do about the same things as ttlscan, nmap, hping, queso, p0f, xprobe, arping, arp-sk, arpspoof, firewalk, irpas, tethereal, tcpdump, etc.